Flash Communication: An Inorganic Version of Alkyne–Azide Cycloaddition: Click-Like Reactions of an <i>o</i>-Carboranyl Iminoborane with Organic Azides

The concept of inorganic-alkyne-based click (iaclick) was introduced. Analogous to the azide–alkyne cycloaddition, o-carboranyl iminoborane 1, an inorganic alkyne, readily underwent cycloaddition with a variety of azides at room temperature and under catalyst-free conditions. This offered a modular synthetic approach to o-carboranyl tetrazaboroles 2a–2h in excellent yields. Stability tests of 2a–2h were performed. These compounds displayed considerable thermal stability, with decomposition temperatures in the range of 195.0–270.8 °C, determined by STA. Air stability tests in the solid state showed that the 1-alkyl derivatives were stable for hours, while the 1-aryl derivatives were stable for weeks. Therefore, upon straightforward incorporation of o-carborane units into organic frameworks, iaclick strategy opens a new avenue for the construction of stable o-carborane-based functional molecules with potential for diverse applications.